Latch for instrument casings



April 16, 1929. B. ELTBRISTOL.- ET Al. 1,709,772

LATCH FOR INSTRUMENT CASINGS -Filed June 27. 1922 Inveno .f- Beh/ne?11.137213@ o, Eagan 11132925630?,

Patented Apr.. 16, 1929.

UNITED STATES :BENNET B. BRISTOL AND EDGAR H. BRIST OL, F FOXBORO,IMASSACHUSETTS,l ASSIGN- OBS T0 THE 4E'OXIBOBO COMPANY, 0F FOXBORO,MASSACHUSETTS, AICORPORATION 0F MASSACHUSETTS.

v Application filed June 27,

VThis invention relates to casings of 'the type used, for example, toenclose the mechanism of recording gages and like instruments and theobject is to provide certain improvements'more particularly relating tothe closure or door of such instruments whereby they will be renderedmore efficient and convenient in use.

The invention will best be understood by reference to the followingdescription of an illustrative embodiment thereof shown by way ofexample in the accompanying drawings, wherein:

' F ig. 1 is a front elevation of a casing such as would be used for arecording pressure gage with parts broken away;

Fig. 2-'s an elevation of the closure fastening;

Fig. 3 is a section on the line 3 3 of Fig.

2o 2 with thepadlock omitted;

Fig. 4 is a similar section showing the lid or door about to close; and

Fig. 5 is a section on the line 5 5 of Fig. 1.

Referring to the drawings, we have there illustrated an instrumentcasing having the cylindrical body portion 7 adapted to'be secured to avertical supporting surface by means of the llange 9 and on which isadapted to close the/glazed door or lid 11 having (see Figs. 3 and 4) acylindrical flange provided with a rabbet'13 adapted to fit over theedge of the cylindrical body portion 7 of the casing. .The door or lid11 may be mounted on one side of the casing by a hinge 15 and is securedat a -dianietrically opposite point by a fastening preferably in theform of a hasp.

We will next describe in detail the particular form of hasp -hereinshown as an example of our invention and which is an instance of anautomatically engaging fasteninfg for the lid 11. As seen from Figs. 4and 3, as the lid 11 closes on its hinges the cylindrical surfaces ofthe body portion 7 of the casing and the flange of the hd 11 move to liesubstantially in the line of approach between them. A hinge leaf 19 ismounted on the flange of the lid 11, preferably by means of screws 21inserted from the interior of the casing and tapping into the hingeleat` 19, and on thisleat is hinged the vslotted hasp 23 having anoutturned end 25 and adapted4 to latch over LATCH FOR INSTRUMENT CASINGS.

1922. Serial No. 571,299.

casing 7 by means of the exterior and interior nuts 29, the end of theshorter leg being presented closely adjacent the body 7 of the casing.There is thus formed a U- shaped loop which may receive a padlock asshown in Fig. 2 and which presents an 4end rounded both on thesidetoward the cover 11 and on the side away therefrom. The first rounded"surface, of course, constitutes a cam to move the hasp 23 to the leftviewing Fig. 4 and as the hasp passes the top of the U it will ridedown'the other rounded surface under the influence, of the spring 29with a camming action tending to draw the cover 11 tightl;v down intoposition.

In accordance with our invention we provide means for resilientlyholdingthe hasp- 23 projected substantially perpendicular to the face of theIlid 11 and inthe line of approach between the two cylindrical surfacesas shown in Fig. 4 and the outturned end thereof constitutes a campermitting the hasp to be displaced to the lt't in Fig. 4 to latch overthe catch 27. Herein we haveshown a spring 29 securedbetween the flangeoithe lid 11 and the hinge leaf 19 and having a short end 30 projectingat the interior and forming a stop to limit counterclockwise movement ofthe hasp and this spring has a reduced portion rebent over the face y ofthe hinge 19 and resting against the outer face of the hasp 23, normallyholding it pressed against the stop 30.

To prevent overstraining of the spring when the end of the hasp isseized by the hand to unlatch the same We preferably pro- \vide a stoplimiting clockwise movement of the hasp and herein a U-shapedmember 31is provided with feet secured by the ends of the screws 21 and has anoffset cross-bar overhanging the end of the spring 29 and adapted tomake contact therewith when the latter is moved-to the left in Figs. 3and 4.

`This cross-bar thus-constitutes a stop preventing movement of the hasptoo far and overstraining of the spring and it furthermore covers theend of the spring and serves as a protection for the hasp mechanism fromblows from the exterior.

The lid 11 in constructions of this kind is heavy vand as the-instrumentis usually supported in the vertical position the lid tends to sag. Itis important that'the lid close accurately with the rabbet 13 fittingover the body 7 of the casing and in particular the alignment of theslot of the h-asp and of the catch 27 should be preserved and this isimportantin the case of an automatically acting closure fastener suchasthe one described. If the parts .are out of alignment the hasp will notengage over the catch as intended. The illustrated embodiment of ourinvention shows one suitable form of hinge 15. The two hinge leaves 'arepreferably secured to the cylindricalsurfaces of the casing and lid bymeans of screws "33 tapped into the same from the interior of the casingand one of the leaves (see Fig. 5) is provided with a long centralknuckle 85 while. the other leaf is provided with the lateral knuckles37. The pintle 39 is in- )serted through the aligned leaves and has aclose it inthe central knuckle 35 and` is free to turn in the knuckles37 so that the lid is mounted as it were on trunnions. By-thisconstruction the bearing surface for the ,pintle is coeX'tensive withthe overall dimension of the hinge which it will be understood must be-relatively restricted on account of the circular contour of the casing.The lid 11 is thus swung on two points relatively far apart and thetendency of the door to sag is counteracted and the alignment of thehasp and its catch is preserved. The construction furthermorefacilitates lubrication of the hinge as the bearings are disposed at theoutside. At the same time the structure is simple and readily assem-vbled.

We have described in detail the particular embodiment of our inventionshown by way of example inthe accompanying drawings but it will'beunderstood that all the detailsl Yillustrated and specifically referredt0 inthe description are not essential to the invention in its broaderaspects but represent a preferred embodiment thereof. The features andcombinations which we consider new and desire to secure by LettersPatentv we shall express in more definite manner by the followingclaims.'

Claims- 1. In combination with two closure members having surfaceslocated when closed substantially in the line of approach between them,a hasp on one member resiliently displaceable outwardly to snap over acatch on the other, and a catch on said other member having a `roundedportion remote from the line of closure over which the hasp is drawnightly to bring together the closure mem- EI'S.

2. In combination with two closure members having surfaces located when"closed substantially in the line of approach between them, a `hasp onone member resiliently displaceable outwardly to snap over a catch onthe other, and a catch on said other member comprising a loop of wire toreceive a padlock or the like and having` a rounded end to cam said haspoutwardly and on entering the same to draw it downwardly to contributeto the tightness of the closure.

3. In a closure of two members having surfaces located when closedsubstantially in the line between them a hasp for one memberdisplaceable outwardly to snap over a catch on the other member andcomprising a securing hinge leaf, a slotted hinge leaf pivoted thereto,a 'spring underlying said first leaf and rebent over said slotted leafand a stop overlying the free end of the spring yto limit movement oftheslotted leaf .against the spring.

4. In a closure of two members having surfaces located when closedsubstantially in the line between them a hasp for one memberdisplaceable outwardly to snap over a catch on the other member andcomprising a securing hinge leaf, a second hinge leaf plvoted theretoand a member beneath said hinge leaf having an end projecting to form astop for said secondP hinge leaf to limit the movement in one directionto a position substantially in alignment with the first leaf, saidmember having at the opposite end a resilient rebent extension bearingon the second leaf to press it toward the stop.

5. In a closure of two members havin surfaces located when closedsubstantial y in the line between them a hasp for one memberdisplaceable outwardly to snap over a catch on the other member andcomprising a securing hinge leaf, a second hingeleaf pivoted thereto, amember beneath` said hinge leaf having an end projectin to form a stopfor said second hinge lea to limit the movement in one direction to aosition substantially in alignment with t e 'first leaf, said memberhaving at the opposite end a resilient rebent extension bearing on thesecond leaf to press it toward the stop anda stop overhanging saidsecond leaf limiting its movement in the other direction.

6. A closure for two members having surfaces located when closedsubstantially in the line between them, a catch on one member, a

hasp on the other member comprising av slotted tinge leaf to engage overthe catch and a securing hinge leaf, a U-shaped member having anelevated cross-bar to protectthe linebetween them, a Catch on one memasa nut to retain the securing leaf and a ber, a hasp on the other memberComspring passing through said member and prising a slotted hinge leafto engage over bearing on the slotted leaf to, resist outward the catchand a securing hinge leaf, a U- swinging thereof and adapted to seat on5 shaped member having an elevated orosssaid cross-bar as a stop. 15

bar toprotect the hasp mechanism and feet In testimony whereof, We havesigned our overlying the securing leaf, screws entered names to thisspecification.' from the interior of said other member passing throughthe securing leaf and tapping 4 BENN ET B. BRISTOL.

- 10 into said feet whereby said member serves EDGAR H. BRSTOL.

